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Re: rdf as a base for other languages

From: Lynn Andrea Stein <lynn.stein@olin.edu>
Date: Fri, 01 Jun 2001 17:50:52 -0400
Message-ID: <3B180E3C.234760B3@olin.edu>
To: pat hayes <phayes@ai.uwf.edu>
CC: Sandro Hawke <sandro@w3.org>, www-rdf-logic@w3.org
> >In message <20010601130755B.pfps@research.bell-labs.com> Peter wrote:
> >
> > >For example, suppose that you wanted to represent propositional formulae
> > >within RDF.  You might do something like:
> > >
> > ><rdf:type x OR>
> > ><component x y>
> > ><component x z>

(and a lot more RDF).  Then pat hayes wrote:

> So, to return to Peter's example: if OR is supposed to be what it
> started out as being (before Peter encoded the logical disjunction
> into RDF), then something needs to know what its truth-conditions
> are: how the truth of a disjunction depends on the truthvalues of its
> compnent subexpressions. But in the RDF encoding, that information is
> not provided as part of the RDF model. So this encoding is not a
> translation of a disjunction into RDF.

You are absolutely right.  By itself -- in the absence of an understanding of
how to interpret the squiggles of RDF -- this is *not* an encoding of a
disjunction in any proper sense.  Further, RDF itself gives NO SUCH
UNDERSTANDING.

That's why various people are trying to write rules for RDF (or RDF-derived
languages):  to provide the "something" that needs to know what
truth-conditions are, let alone what the truth conditions obvious to human
readers of but not inherent in the RDF excerpt from Peter, above.

(Note that this is separate from which statements, x, y, or z, might be
asserted or true or whatever, which is another discussion going on on this
same thread).

Oh, and:

> You refer to a closed-world assumption, but I fail to see how a CWA
> can specify the truthconditions for disjunction (or anything else.)

I believe that this was a joke referring to Sandro's attempts to intuit
Peter's meaning.

Lynn
Received on Friday, 1 June 2001 17:51:03 GMT

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